Aesop's Fables, translated by Laura Gibbs (2002)

Some field-mice were playing in the woods where a lion was sleeping when
one of the mice accidentally ran over the lion. The lion woke up and immediately
grabbed the wretched little mouse with his paw. The mouse begged for mercy,
since he had not meant to do the lion any harm. The lion decided that
to kill such a tiny creature would be a cause for reproach rather than
glory, so he forgave the mouse and let him go. A few days later, the lion
fell into a pit and was trapped. He started to roar, and when the mouse
heard him, he came running. Recognizing the lion in the trap, the mouse
said to him, 'I have not forgotten the kindness that you showed me!' The
mouse then began to gnaw at the cords binding the lion, cutting through
the strands and undoing the clever ingenuity of the hunter's art. The
mouse was thus able to restore the lion to the woods, setting him free
from his captivity. Let no one dare to harm even the smallest among us.

Note: For a quite different fable about a lion and a mouse, see Fable
245.

Source:
Aesop's Fables. A new translation by Laura
Gibbs.
Oxford University Press (World's Classics): Oxford, 2002.
NOTE: New
cover, with new ISBN, published in 2008; contents of book unchanged.